Abstract: This dissertation presents the results of a study investigating the diachronic development of complexity, accuracy, and fluency in second language oral production. Consistent with the axiology of dynamic systems theory, the mutable nature of the complex linguistic system as well as the emphasis on intra-individual variability are underscored within the methodological considerations informing this study. As such, a process-oriented, non-linear time series analysis was carried out to address the following research questions: (a) In what ways do the constructs of complexity, accuracy, and fluency develop longitudinally in a single untutored learner of ESL across multiple language tasks?; (b) To what extent do the relationships between these constructs change over one academic year in an English-speaking context?; and (c) In what ways does the diachronic development of syntactic complexity exhibit the characteristics of self-similarity (i.e., fractality)? Data were collected from an individual untutored learner of English as a second language on a weekly basis from two disparate oral tasks (viz., dialogic conversation and monologic narrative) for the period of one academic year. The density of data collection—consistent with a complexity perspective—provided sufficient granularity for the developmental trajectories of nine subcomponents of complexity, accuracy, and fluency to be scrutinized in terms of their growth, regression, and, equally, the synergistic relationship among these constructs.Results of the non-linear time analysis confirm several assumptions regarding the nature of language as a complex dynamic system. Findings illustrate the ways in which grammatical complexity, accuracy, and fluency develop uniquely across tasks. In addition, the complex relationships between these domains demonstrate the dynamism within the interconnectedness of the components of the complex linguistic system and, ultimately, how such relationships develop uniquely over time to support language development. In addition, results indicate that, typical of chaotic systems, language development demonstrates self-similarity (i.e., fractality) across temporal levels and equally passes through periods of bifurcation in which complexity, accuracy, and fluency interact uniquely to promote the transition between attractor states.
Keywords: Bifurcations,CAF,Complexity dynamic systems,Fractals, Second language development